Glossary of Terms Part II

GLOSSARY OF TERMS

Albinistic - Any individual displaying an alteration in melanin metabolism or defective
melanosome biogenesis. Inos, Fallows and Cinnamons (aka Fawn in the Zebra but not Fawn
in the Society) are some examples of albinistic finches.

Albino - An individual which lacks all eye and skin pigments. Albino is the direct result of a
knockout mutation in tyrosinase, the rate limiting and essential enzyme in melanin synthesis.
In white ground birds, feathers will be pure white, feet pink and eyes red. In Societies, Albino
is an autosomal recessive mutation and is also referred to as nonsex-linked Ino (NSL). In yel-
low ground birds, a second carotenoid mutation is still required to create an Albino.
Examples: Society Albino and Albino Gouldians.

Allele - Alternative form or variant of a gene or locus. A deviation from the wild type. One of
different possible genes that can exist at a specific site on a chromosome. In the Example Aa,
A = 1st allele, and a = 2nd allele.

Autosomal - Occuring on or related to any chromosome other than the sex (gender determin-
ing) chromosomes.

Backcross - A mating between a heterozygote and a homozygote. Most typically, this is a
pairing between a split progeny and another bird which is genetically identical to one parent
for the gene or trait in question.

Bengalese Finch - Another name for the Society Finch, affectionately shortened to 'Bengies'.

Black Brown - The darkest Euro Bengalese Finch color. This is the default or wild type color.
In American Societies, Chocolate is the Black Brown analog. See “Euro.”

CFW (Abreviation for Chestnut Flanked White Zebra Finch) - There are two CFW alleles: R or
Regular CFW, and C or Continental CFW. Along with Lightback (LB), all are part of the CFW
multiple allelic series. C CFWs are albinistic. Many similarities exist between C CFWs and
Inos.

Carotenoids - Colorful red, orange or yellow pigments responsible for bright feather, skin and
bill coloration in some bird species. Examples include the red beak and leg color of Shafttails
or Zebras, and the red or orange head color in Gouldians.

Creamino - The common name for sex-linked Ino in white ground finches. Creaminos are off-
white with red eyes. Sometimes written as Cream-Ino.


Crossover - Common term for a genetic recombination event between two homologous chro-
mosomes. Examples: LB-Fawn, CFW-Fawn and BC-GC in Zebra Finches. See also
“Recombination.”

Cull - To remove a bird with undesirable traits from a breeding program. A form of negative
selection performed by breeders. While many think this means to kill, it does not. I cull my
birds and then sell them.

Double Factor (DF) - A term used for co-dominant mutations when both mutant alleles are
present in an individual. Example: DF Florida Fancy in Zebra Finches. Also used for domi-
nant mutations though many times, DF is considered lethal. Examples: DF Black Face in
Zebras or DF Red Head in Gouldians.

Eumelanin - One of two major classes of melanin pigment. Eumelanin is normally quite dark
being black, gray or dark brown in color.

Euro - A term coined by the late Bob Rittman to describe a highly selected form of Bengalese
Finches. Euros are known for their intensive colors and are commonly called Black Browns,
Mocha Browns and Red Browns. Additional distinguishing features of the Euro include bold
belly scaling & solid bib/breast coloration. Euros are the result of a 3-way cross between
Black Headed Nuns (Lonchura malacca) x Society Finch (Lonchura striata domesticus) and
then crossed again to White Headed Nuns (Lonchura maja). Red Browns may also have
been crossed with Chestnut Breasted Mannikins (Lonchura castaneothorax). A debate contin-
ues as to whether Euros should be considered man created hybrids, a variant, a strain or a
separate subspecies of Lonchura. Euros are NOT a simple genetic trait or single gene muta-
tion. Just because a Euro is crossed with a Society, it does not mean that Euro progeny are
produced. See “Euro Influenced. “

Euro Influenced - Progeny which are the result of further backcrossing of a Euro to an
American Society Finch. These birds tend to not be as colorful or have as intensive belly
scales as Euros which haven't been further backcrossed to non-Euro Society Finches. Euro
Influenced birds are intermediate in phenotype, somewhere between a quality Euro and an
American Society.

Fallow - A light yellowish brown or yellowish brownish green color. In birds, Fallow is an
albinistic mutation with reddish eyes.

F1 - Literally means 'First Filial'. The first generation progeny (offspring) from a cross.

Gene - A heritable trait that occurs within the genetic material (DNA) of an organism. A funda-
mental and functional unit of heredity.

Genotype - All the genetic material of an individual bird including all recessive genes which
cannot be readily observed or measured.

Grayino - A combination mutation of Gray and Ino in Society Finches.

Heterozygote - Commonly called 'split' and often written as dominant mutation/recessive muta-
tion. Example: Normal Gray/Black Cheek Zebra finch. An individual with two different alleles
(variants) at a given locus (gene) on homologous (matching) chromosomes. Heterozygosity is
typically represented by genetic symbols. Example: Aa, where the capital letter indicates a
dominant allele, and the lower case letter indicates a recessive allele. For recessive muta-
tions, heterozygotes possess one dominant allele (in this case A) and will appear normal or
wild type for that trait. The recessive allele will be hidden and cannot be seen. Example:
Black Headed Gouldians. For co-dominant mutations, the heterozygote will have an intermedi-
ate phenotype. Examples: single factored Florida Fancy in Zebra Finches or in single factored
purple breasted Yellow Backed male Gouldians. For dominant mutations, the full mutant phe-
notype can be seen even in the heterozygote. Examples: single factored Crested in Zebra
Finches or Society Finches.

Heterozygous - See “heterozygote.”

Homologous Chromosomes - A pair of matching chromosomes that have the same size,
shape and complement of genetic loci or genes. In diploid organisms such as humans or
birds, chromosomes occur in pairs, and identically paired chromosomes are known as
homologs. Example: Humans have 46 total chromosomes, 23 chromosome pairs, with 22
homologous chromosomes. (The sex chromosomes [XY] are paired, but they are NOT homol-
ogous.)

Homozygote - An individual who has inherited identical alleles (variants) at a given locus
(gene) on homologous (matching) chromosomes. Examples: AA or aa. Penguin in Zebra
finches or Fawn in Society finches or Shafttails. All these examples are homozygous reces-
sive. A double factored Red Headed Gouldian is homozygous dominant.

Homozygous - See “homozygote.”

Hybrid - Offspring from mating individuals from 2 different species or 2 different genera.

Ino - Generalized term for severely reduced pigment mutations in birds resulting in little to no
skin, eye or feather pigments. The Ino suffix is added to various mutations to create common-
ly used terms like Creamino or Lutino. The root of the term comes from Greek mythology. Ino
was the white goddess. See also “Sex-Linked Ino,” “Non Sex-Linked Ino,” “Albino,”
“Creamino” and “Lutino.”

Intergeneric Hybrid - The offspring from mating birds of two different genera. Example:
Society Finch (Lonchura striata domestica) x Shafttail Finch (Poephila acuticauda).

Interspecific Hybrid - The offspring from mating birds of two different species. Example: White
Rumped Mannikin (Lochura striata) x White headed Nun (Lonchura maja).

Intraspecific Hybrid - The offspring from mating of 2 different subspecies. Example: Zebra
Finch (Taeniopygia guttata castanotis) x Timor Zebra Finch (Taeniopygia guttata guttata).

Knock out mutation - A completely disrupted or inactivated gene such that its protein product
is totally nonfunctional. Example: Albino in Society Finches.

Lacewing - A Budgerigar recombination mutation involving the sex-linked Ino and Cinnamon
mutations. The Lacewing mutation is different and distinct from either the Cinnamon or Ino
mutations alone. They are also red eyed.

LB - Abbreviation for Lightback Zebra Finch. One of three alleles of the sex-linked CFW multi-
ple allelic series.

Locus (plural Loci) - The location of a gene on a chromosome or a genetic map.

Linkage - The proximal relationship of two genes or loci on a chromosome. The closer togeth-
er these two genes are relative to one another, the more tightly they are linked, and there is a
lower likelihood of crossover or genetic recombination.

Lutino - The common name for sex-linked Ino in yellow ground birds. Lutinos are bright yellow
with red eyes.

Melanin - A class of biochemically complex pigments composed of long polymeric chains.
Melanin pigments are synthesized in melanocyte epidermal cells where they may color the
skin. They are also deposited in developing feather follicles during the molt giving black,
brown and rust coloration to feathers.

Melanoblast - An epidermal cell, the developmental precursor for a melanocyte.


Melanocyte - An epidermal (skin) cell which is the site of melanin synthesis. Melanocytes are
in close association with feather tracts.

Mocha Brown - Medium brown shade of Euro Bengalese Finch. In American Societies,
Chestnut is the Mocha Brown analog. See “Euro.”

Modifier - A minor gene that does not act on its own but rather affects the expression of anoth-
er gene. Modifiers cannot be visualized in all phenotypes. Example: Fawn washed back in
CFW Zebras.

Morph - Common term for a color variant or a color mutation. A distinct genetic form.

Mule - F1 hybrid offspring from an interspecific or intergeneric hybridization. Mules are typi-
cally sterile.